/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
'use strict';

import { Range, Position, SelectionRange, TextDocument } from '../cssLanguageTypes';
import { Stylesheet, NodeType } from '../parser/cssNodes';

export function getSelectionRanges(document: TextDocument, positions: Position[], stylesheet: Stylesheet): SelectionRange[] {
	function getSelectionRange(position: Position): SelectionRange {
		const applicableRanges = getApplicableRanges(position);
		let current: SelectionRange | undefined = undefined;
		for (let index = applicableRanges.length - 1; index >= 0; index--) {
			current = SelectionRange.create(Range.create(
				document.positionAt(applicableRanges[index][0]),
				document.positionAt(applicableRanges[index][1])
			), current);
		}
		if (!current) {
			current = SelectionRange.create(Range.create(position, position));
		}
		return current;
	}
	return positions.map(getSelectionRange);

	function getApplicableRanges(position: Position): number[][] {
		const offset = document.offsetAt(position);
		let currNode = stylesheet.findChildAtOffset(offset, true);

		if (!currNode) {
			return [];
		}

		const result = [];

		while (currNode) {
			if (
				currNode.parent &&
				currNode.offset === currNode.parent.offset &&
				currNode.end === currNode.parent.end
			) {
				currNode = currNode.parent;
				continue;
			}

			// The `{ }` part of `.a { }`
			if (currNode.type === NodeType.Declarations) {
				if (offset > currNode.offset && offset < currNode.end) {
					// Return `{ }` and the range inside `{` and `}`
					result.push([currNode.offset + 1, currNode.end - 1]);
				}
			}

			result.push([currNode.offset, currNode.end]);

			currNode = currNode.parent;
		}

		return result;
	}
}
